Question

During refraction of light, which of the following quantities does not change?
A. Velocity
B. $\lambda$
C. Amplitude
D. Frequency

Answer 1

Hint:Recall the basics physical quantities related with a wave. Also recall the process of refraction of the light. From this information, check which of the physical quantities related with the light changes when the light passes from one medium to the other medium or undergoes refraction.

Complete answer:
The phenomenon in which the ray of light bends or changes its incident direction when it passes from one medium to another medium is known as refraction of light.

When a ray of light passes from one medium to another medium, the refractive index of the medium changes. The velocity of the light ray depends on the refractive index of the medium. Hence, the velocity of the ray of light changes when it undergoes refraction.Hence, the option A is incorrect.

The symbol $\lambda$ represents the wavelength of the ray of light. The wavelength of the light is directly proportional to the velocity of the light ray. The velocity of light changes on changing the medium by the light. Hence, the wavelength of the light also changes when it undergoes refraction.Hence, the option B is incorrect.

We know that there is no material which is ideal for refraction and does not absorb any energy from the wave passing through it. Hence, when the ray of light passes from one medium to the other medium, there is absorption of some energy of the light ray and hence, the amplitude of the light ray changes.Hence, the option C is incorrect.

When a ray of light passes from one medium to the other medium, the physical quantities related with this ray of light such as velocity, wavelength, amplitude, etc changes such that the frequency of the wave always remains the same.

Therefore, the frequency of the light does not change on its refraction.Hence, the correct option is D.

Note: The students should keep in mind that the physical quantities like velocity, amplitude and wavelength changes when it undergoes refraction. But these physical quantities can increase or decrease depending on the media through which it travels (means either from rarer to denser medium or denser to rarer medium).